Foamless shoe

ABSTRACT

The present invention is a composite sole used in footwear. The composite sole comprises of two components, a foot support that suspends the foot and a structural chassis. The foot support is a flexible material that attaches to the perimeter of the structural chassis and conforms to the foot. The structural chassis provides rigidity and the foot support provides sufficient strength to suspend the foot during rigorous physical activity. The chassis and foot support performs similarly to that of a trampoline; however, its function has a plurality of features not found in a trampoline. The structural chassis is designed to provide a multitude of physical and performance characteristics in the heel, arch, forefoot and toe area to assist in pronation, plantar support, energy return, upper shoe comfort, toe-off and cushion at impact. The structural chassis has air vents, allowing air to enter and the foot support includes perforations allowing this air to ventilate the underside of foot.

BRIEF SUMMARY

The present invention is a composite sole for footwear. comprising of an attached foot support and a structural chassis.

BACKGROUND

The footwear industry is in constant pursuit to increase comfort, performance and reduce cost. Within the past years, sustainability has also become a focus because athletic shoes still use a foam midsole which deteriorate and goes flat in a short time. This disposable product causes concern because millions of pairs end up in landfills worldwide and recycling has been limited due to dissimilar materials found in the athletic shoe. Foam has been the material of choice for approximately fifty years, however, this material has many drawbacks; foams inherent low density and strength can cause many injuries to both consumers and athlete. An athlete running can easily generate two-three times bodyweight at impact, foams low density causes it to compress, creating a denser product at impact, this induces shock to the foot, knees, back and other areas causing runner related injuries. Ankle injury also result from foams low physical strength, allowing the ankle to turn under. Achilles and plantar injuries also result because a soft foam midsole allows the heel and arch area in a shoe to compress allowing tendons to stretch beyond their natural range of motion. Foams also an insulator, the underside of foot has no way to ventilate, this increases blisters, perspiration, odor and increases heart rate, requiring more blood to the foot. Foams low strength and density causes it to absorb energy, even with a carbon fiber plate, the product has low stiffness and energy return compared to other carbon fiber products without the use of foam in tennis, golf, archery and a multitude of other industries

Many energy return devices have been invented for footwear, however, most have had little success due to increased cost of additional parts and increased cost in assembly, each additional part also increases product delivery risk by 100%, due to vendors/transportation's inability to deliver parts on time. Many energy return devices and composite frame shoes are of odd shape, size and height, esthetics and physical features different from the historically traditional footwear market are often times not accepted by the market. The present invention was developed to fit within the same footprint and height of the current footwear market and to be manufactured at the lowest possible cost with the fewest number of parts, relative to features. The invention has high energy return, low impact, complete underfoot cooling along with increased product life because the carbon fiber composite chassis flexes with no appreciable loss in performance. This invention address's many of the above issues along with additional features and benefits currently not found in the footwear market.

DETAILED DESCRIPTION

This invention conveys the scope of the disclosure to someone with ordinary skills in the art. The sole referred to herein is the structural chassis and foot support, this makes up the sole in footwear. The completed footwear would comprise of an upper, structural chassis, attached foot support and outsole. The structural chassis and foot support suspends the foot during rigorous physical activity. The structural chassis is injection molded using thermoplastic with carbon and glass fiber. Nylon, polycarbonate and other high strength thermoplastics can be used with fiber reinforcement to increase physical properties and reduce weight. Material selection along with many other design criteria are used to control manufactured cost and desired performance properties within the structural chassis. High impact sports and higher body weight may require higher stiffness within the structural chassis. The foot support and structural chassis design are used to keep the foot suspended at impact. The invention uses force at impact to flex the structural chassis, this in turn allows downward foot travel and provides cushion for the foot and reduces impact, this action simultaneously stores and releases this kinetic energy to increase energy return and enhances footwear performance. Insufficient structural chassis stiffness may allow excessive travel, allowing the foot to contact the bottom of the structural chassis, Inversely, excessive stiffness in the structural chassis can restrict downward travel and cause insufficient cushion and discomfort. Many materials and manufacturing methods may be used to produce the structural chassis; compression molding, hand layup, sandwich construction, resin infusion, prepreg laminates using carbon fiber, glass, aramid, thermoset resin and thermoplastic polymers may all be used with the above methods and are only a few of the methods and materials that can be used to produce the structural chassis and are well known in the art Words describing an attribute of the invention are for reference only, and may be used interchangeably, this does not limit the scope of invention.

The structural chassis has integral longitudinal and transverse ribs, these ribs allow the structural chassis to be produced using less material. Openings may also be included between ribs on both horizontal and vertical surface to reduce weight, add air vents and increase flexibility where needed. The structural chassis is specifically designed with a multitude of design and physical characteristics that control comfort and performance experienced in the footwear. The heel, arch, forefoot and toe area are designed with specific characteristics. Modifications may be made universally or within specific areas. These areas of the structural chassis called zones are designed using wall height, wall thickness, rib height, rib thickness and spacing to control desired attributes. Because width of the foot varies, transverse stiffness may require modification within the structural chassis, the heel is approximately 50% narrower than the forefoot, this shortened transverse distance, if not designed accordingly, could have significantly more stiffness compared with the forefoot and make the footwear uncomfortable on heel strike and pronation. The structural chassis is divided into three areas, this is done to accommodate the foot, which is not symmetrical in shape or in its function. Foot pronation is considered in design of the foot support and the structural chassis, this accommodates the twisting action starting on the lateral and turning inwards towards the medial. The foot support profile and bottom profile of the structural chassis referred to as bottom rocker is further taken into consideration for the chassis desired performance and intended use. The chassis has several specific areas, herein referred to as zones.

Zone 1 is designed for but not limited to, heel strike cushion, pronation and heel travel distance. Because the foot naturally pronates, the lateral side of a heel strike experiences more impact compared to the medial side and is considered in design. The heel transverse distance compared to the forefoot requires more flexibility for comparable cushion compared to the forefoot which has a 50% longer transverse distance. The heel zone is also designed to rotate on its axis to allow natural foot pronation, insufficient tortional flexibility in this zone could cause discomfort, due to the structural chassis inherent stiffness, this also, could resist foot pronation if not properly designed. Vertical wall height, wall thickness on both vertical and horizontal surface, rib height and spacing are used to control tortional, horizontal, longitudinal and vertical properties within the structural chassis. Openings between ribs on both vertical and horizontal surface in the structural chassis may be used to decrease weight and increase flexibility. All the above methods may be used to increase or decrease downward heel travel. Controlling heel travel can protect the Achilles from over extending. Height at the heel compared to forefoot is also taken in consideration when designing the desired drop or offset in footwear.

Zone 2, this zone is primarily made up by the plantar fascia. The structural chassis may be designed with a rise on the medial side of the structural chassis, arch support may vary in height and stiffness to protect the plantar fascia from over extending. Zone 1 modifications may also be used in this zone for performance. Zone 2 typically experiences less pressure at impact compared to zones 1 and 3, this may allow weight savings in this area.

Zone 3, this area is primarily made up of the forefoot and toe area.

This area has the largest area and experiences the most impact from the majority of athletes. Because the transverse distance is approximately fifty percent longer compared to the heel it requires more stiffness to a achieve comparable cushion. The medial side at the first metatarsal experiences the most pressure at impact, this requires more strength and rigidity compared to the lateral side. Zone 1 modifications may also be used in this zone. Toe height dictates the point of toe-off, when the toe leaves the ground, sufficient toe height and bottom rocker radius are necessary for forefoot roll and toe performance, this is necessary because as the foot hinges the heel lifts and creates greater pressure on the upper. Poor roll performance at the forefoot and insufficient toe height could resist foot movement and cause discomfort on top of the laces and also cause heel slip. The foot support profile and bottom rocker longitudinal and transverse profile are designed and operate independently of one another in zones 1-3. The structural chassis in zones 1-3 has a multitude of design variation, overlap and is not limited by examples given above. Other materials, components may be fabricated separately and included in the structural chassis and or substituted for the thermoplastic fiber composite, at the metatarsal, toe and other areas, allowing more flexibility or rigidity where desired. The foot support may have multiple size and shape openings allowing the foot support to ventilate the underside of foot. The flexible foot support fabric conforms to the bottom of foot and is Kevlar by DuPont. Denier of Kevlar is determined by weight of athlete and intended use. Many other low stretch high strength fibers and tows of glass, carbon, uhmwpe, ballistic nylon can be used. It is also understood a multitude of natural, synthetic material with a plurality of weave direction, biaxial layers, open mesh, individual strands for lacing could also be used to produce the foot support. Attachment of the foot support to the perimeter of the structural chassis is done with Adhesives, however, mechanical fasteners can be used, the foot support may be molded in-situ in the injection molding process. Specific adhesive and method of attachment is determined by compatibility between foot support and structural chassis material. The rubber outsole may be replaced by having integral barbs and or barbed fasteners when pushed through a hole in the chassis provides an undercut to hold the outsole in place. The outsole can also be fastened by providing an undercut along the exterior wall of chassis wherein the outsole can slide on and or clips in. Shoe upper may also be replaced by providing a track or other means around the perimeter. Both the outsole and upper can use various fasteners and holding devices already in use in consumer products and are well known. The structural chassis may also be over molded, this can combine an outsole, sidewall bumper and perimeter cushion and the strobel turn, this process is usually used to enclose the structural chassis within a rubber exterior.

PRIOR ART

-   U.S. Pat. No. 9,907,353B2 Energy return sole, -   U.S. Pat. No. 9,021,719B2 Shoe spring and shock absorbing system

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 Injection molded structural chassis

FIG. 2 Foot support

FIG. 3 Shoe upper

FIG. 4 Outsole

FIG. 5 Air vent openings in chassis

FIG. 6 Perimeter rubber bumper 

The invention claimed is:
 1. A sole comprising of: a base component having a manufactured structural chassis, at least one foot support to suspend the foot; wherein structural chassis is injection molded with glass, carbon fiber; wherein said structural chassis modification is polymer selection, fiber reinforcement, percentage and type; wherein said structural chassis modification is openings on vertical and horizontal surface; wherein said structural chassis modification is wall thickness on vertical, horizontal surface, wall height, rib height, rib thickness and rib spacing; Wherein said structural chassis modification is it least one additional material; wherein said structural chassis modification is it least one material substitution for thermoplastic fiber composite;
 2. A sole according to claim 1, wherein structural chassis includes a foot support of Kevlar, ballistic nylon, uhmwpe.
 3. A sole according to claim 2, wherein foot support has multiple openings allowing air penetration.
 4. A sole according to claim
 3. wherein foot support has sufficient flexibility to conform to underside of foot.
 5. A sole according to claim 1, wherein structural chassis has sufficient rigidity to suspend foot during rigorous physical activity.
 6. A sole according to claim 4, wherein foot support has sufficient strength to suspend foot during rigorous physical activity.
 7. A sole according to claim 5, wherein structural chassis bottom profile and foot support profile are on opposite side of structural chassis and may act Independent of one another in vertical, longitudinal and transverse direction.
 8. A sole according to claim 7, wherein structural chassis has multiple air vent openings on vertical and horizontal surface.
 9. A sole according to claim 8, wherein structural chassis channels air Through multiple air vent openings through openings in foot support.
 10. A sole according to claim 9, wherein the channeled air through openings in foot support ventilates foot.
 11. A sole according to claim 10, wherein structural chassis having a replaceable outsole.
 12. A sole according to claim 11, wherein structural chassis having a replaceable upper.
 16. A sole according to claim 1, wherein structural chassis includes holes for outsole and or upper installation.
 17. A sole according to claim 1, wherein structural chassis has undercuts for outsole and or upper installation. 